The total number of basic groups in the following form of lysine is:

Identify the fibrous protein from the following.

The isoelectric point is a

Identify the $N$-terminal and $C$-terminal $\alpha$-amino acids respectively in the following polypeptide fragment: $Ala-Gly-Ser-Tyr-Gly$.

What is the monomer of a polypeptide?

The correct structure of the dipeptide gly-ala is